In recent years, there has been an outstanding progress in a digitalization technology of a broadcast system. In a terrestrial television broadcast system in Japan or Europe, a modulation scheme called an orthogonal frequency division multiplexing (OFDM) resistant to an influence of a multi-path interference is employed in modulation.
The OFDM scheme is also employed in a European cable broadcasting system. According to a second generation European cable digital broadcasting standard DVB-C2, in order to prevent an interference with other communication channels, data is not transmitted by setting a transmission power to zero in a certain frequency band called a notch while a signal is transmitted (for example, refer to Non-Patent Document 1).